Multilayer hybrid polypropylene composite with single and wood-polymer composites

Wood polymer composites are materials with pseudoplastic and viscoelastic properties. They have yield stress and exhibit slip during flow. Studies on extrusion and rheology, as well as on process modeling of these highly filled materials are limited. Extensive rheological and extrusion modeling studies on the wood polymer composite based on the polypropylene matrix were performed. Viscous and slip flow properties were determined (with Rabinowitsch, Bagley, and Mooney corrections) at broad (extrusion) range of shear rate and temperature, using a high-pressure capillary rheometer. Rheological models of Klein and power-law were used for flow modeling, and Navier model was applied for slip modeling. A novel global computer model of WPC extrusion with slip effects has been developed, and process simulations were performed to compute the extrusion parameters (throughput, power consumption, pressure, temperature, etc.), and to study the effect of the material rheological characteristics on the process flow. Simulations were validated experimentally, and were discussed with respect to both rheological and process modeling aspects. It was concluded that the location of the operating point of extrusion process, which defines the thermo-mechanical process conditions, is fundamentally dependent on the rheological materials characteristics, including slip effects.

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Dielectric Properties of Wood-Polymer Composites: Effects of Frequency, Fiber Nature, Proportion, and Chemical Composition

Journal of Composites Science ◽

10.3390/jcs5060141 ◽

2021 ◽

Vol 5 (6) ◽

pp. 141

Author(s):

Imen Elloumi ◽

Ahmed Koubaa ◽

Wassim Kharrat ◽

Chedly Bradai ◽

Ahmed Elloumi

Keyword(s):

Dielectric Properties ◽

Polymer Composites ◽

Wide Frequency Range ◽

Dielectric Constants ◽

Cellulose Content ◽

Wood Fibers ◽

Low Frequencies ◽

Wood Polymer ◽

Wood Polymer Composites ◽

New Applications

The characterization of the dielectric properties of wood–polymer composites (WPCs) is essential to understand their interaction with electromagnetic fields and evaluate their potential use for new applications. Thus, dielectric spectroscopy monitored the evolution of the dielectric properties of WPCs over a wide frequency range of 1 MHz to 1 GHz. WPCs were prepared using mixtures of different proportions (40%, 50%, and 60%) of wood and bark fibers from various species, high-density polyethylene, and maleated polyethylene (3%) by a two-step process, extrusion and compression molding. Results indicated that wood fibers modify the resistivity of polyethylene at low frequencies but have no effect at microwave frequencies. Increasing the fiber content increases the composites’ dielectric properties. The fibers’ cellulose content explains the variation in the dielectric properties of composites reinforced with fibers from different wood species. Indeed, composites with high cellulose content show higher dielectric constants.

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Analysis of Creep of Wood-Polymer Composites

IOP Conference Series Materials Science and Engineering ◽

10.1088/1757-899x/1079/4/042022 ◽

2021 ◽

Vol 1079 (4) ◽

pp. 042022

Author(s):

M A Elesin ◽

N A Mashkin ◽

V F Khritankov ◽

N V Karmanovskaya

Keyword(s):

Polymer Composites ◽

Wood Polymer ◽

Wood Polymer Composites

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Analysis of wood polymer composites by two-stage pyrolysis–GC/MS

Journal of Analytical and Applied Pyrolysis ◽

10.1016/j.jaap.2008.09.008 ◽

2008 ◽

Vol 83 (2) ◽

pp. 213-219 ◽

Cited By ~ 29

Author(s):

Clemens Schwarzinger ◽

Manuela Leidl ◽

Robert Putz

Keyword(s):

Polymer Composites ◽

Two Stage ◽

Wood Polymer ◽

Wood Polymer Composites

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Mechanical Properties and Decay Resistance of Wood Polymer Composites (WPC)

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.264-265.819 ◽

2011 ◽

Vol 264-265 ◽

pp. 819-824 ◽

Cited By ~ 1

Author(s):

Md. Rezaur Rahman ◽

Sinin Hamdan ◽

M. Saiful Islam ◽

Md. Shahjahan Mondol

Keyword(s):

Polymer Composites ◽

Young’S Modulus ◽

Modulus Of Elasticity ◽

Young's Modulus ◽

Decay Resistance ◽

Modulus Of Rupture ◽

Wood Polymer ◽

Static Young’S Modulus ◽

Wood Polymer Composites ◽

Wood Polymer Composite

In Malaysia, especially Borneo Island Sarawak has a large scale of tropical wood species. In this study, selected raw tropical wood species namely Artocarpus Elasticus, Artocarpus Rigidus, Xylopia Spp, Koompassia Malaccensis and Eugenia Spp were chemically treated with sodium meta periodate to convert them into wood polymer composites. Manufactured wood polymer composites were characterized using mechanical testing (modulus of elasticity (MOE), modulus of rupture (MOR), static Young’s modulus) and decay resistance test. Modulus of elasticity and modulus of rupture were calculated using three point bending test. Static Young’s modulus and decay resistance were calculated using compression parallel to gain test and natural laboratory decay test respectively. The manufactured wood polymer composites yielded higher modulus of elasticity, modulus of rupture and static Young’s modulus. Wood polymer composite had high resistant to decay exposure, while Eugenia Spp wood polymer composite had highly resistant compared to the other ones.

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Selected properties of flat-pressed wood-polymer composites for high humidity conditions

BioResources ◽

10.15376/biores.15.3.5141-5155 ◽

2020 ◽

Vol 15 (3) ◽

pp. 5141-5155

Author(s):

Piotr Borysiuk ◽

Jacek Wikowski ◽

Krzysztof Krajewski ◽

Radosław Auriga ◽

Adrian Skomorucha ◽

...

Keyword(s):

Polymer Composites ◽

Polymer Composite ◽

Urea Formaldehyde ◽

Core Layer ◽

Modulus Of Rupture ◽

Formaldehyde Resin ◽

High Humidity ◽

Wood Polymer ◽

Wood Polymer Composites ◽

Wood Polymer Composite

This study investigated the possibility of applying flat-pressed wood-polymer composites in conditions of high humidity. The experiment involved three variants of wood-polymer composite panels 16 mm thick, and 680 kg per m3 density. The wood particles were bonded with polyethylene. The share of polyethylene in the core layer was fixed at 50%, while in the face layers the content was varied (40%, 50%, or 60%). The following parameters were examined: modulus of rupture (MOR), modulus of elasticity (MOE), internal bond (IB), screw holding (SH), thickness swelling (TS), water absorption (WA), susceptibility to drilling and milling, wettability and surface free energy, and resistance to mold. The results were compared to particleboard glued with urea-formaldehyde resin. The wood-polymer composite had lower MOR and MOE values and similar IB and SH values. The panels indicated a remarkably higher water resistance (lower TS and WA values) with good surface wettability and high resistance to mold fungi. Additionally, the composites were easier to machine, e.g. drilling or milling, in comparison to standard particleboards.

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